Aquaponics system functions mainly based on a principle of creature interaction that is existing in the nature. It is an eco-system in which plants, fishes, bacteria or microbes are fundamental elements, and excrements of the fishes are transformed to nutrients of plants. In a broader sense aquaponics is an eco-culture or composite cultivation technique. In practice the system generally adopts an approach of nitrifying waste water of culture farming through bacteria to produce nutrients needed by growing of plants. The waste water is finally transformed to the nutrients needed by the plants and absorbed. The water also is purified in the process. Hence the entire aquaponics system is eventually a closed water circulation system. It provides the advantage of culture farming without the need of changing water and growing vegetables without the need of watering. Meanwhile, the aquaponics system also incorporates microbes activities, hence is an organic cultivation and culture technique, and can provide more natural and healthy foods to people.
A conventional aquaponics system 1 is designed in a concept as shown in FIG. 1. It mainly includes a bell siphon 11 which consists of a bell hood 111, an inner tube 112 and an external air tube 113. The bell hood 111 has a plurality of apertures 114. A cultivation liquid storage tank 12 is provided which has a liquid pumping device 13 located inside to continuously pump liquid to a plant cultivation pot 14. When the cultivation liquid enters the bell hood 111 through the apertures 114 and reaches an upper spot of the inner tube 112, namely the upper liquid level where a plurality of cultivated plants 15 can absorb the cultivation liquid, if the cultivation liquid flows out through the inner tube 112 at a sufficient amount to form a water film and make the pressure inside the bell hood 111 smaller than the external atmospheric pressure, the bell siphon 11 generates a siphonage action, and the external atmospheric pressure pushes the cultivation liquid to flow back to the cultivation liquid storage tank 12. When the cultivation liquid drops to a lower liquid level the external air enters the bell hood 111 via the external air tube 113 to break liquid column and stop the siphonage action, then the cultivation liquid stop flowing back. Therefore the liquid level in the plant cultivation pot 14 reaches the lower liquid level to allow the roots of the cultivated plants to breath with oxygen. At the same time, the liquid pumping device 13 continuously pumps the cultivation liquid until reaching the higher liquid level to achieve circulation of the cultivation liquid, thereby make cultivation of the plants possible.
However, all the present bell siphon 11 adopts the internally built approach and is embedded in the plant cultivation pot 14, and is prone to skewing and results in failure of generating siphonage action desired, or has the inlet of the cultivation liquid jammed by dirt, stones or external objects that prohibits external air from entering the siphon air chamber to break the liquid column This makes the siphonage action fails to stop the liquid pumping device 13 to pump the cultivation liquid to the plant cultivation pot 14 and maintain the siphonage action to allow flow back of the cultivation liquid to the cultivation liquid storage tank 12 to keep liquid balance as desired. Namely, the liquid level in the plant cultivation pot 14 cannot rise to the higher liquid level to allow the plants 15 to get the cultivation liquid, but merely maintain at the lower liquid level, thus fails to achieve the liquid level circulation effect. In addition, the bell siphon 11 also has the external air tube 113 as shown in FIG. 1 to aid entry of external air when the actual liquid level drops to the lower liquid level, but it still does not improve the problems of skewing of the bell siphon 11 installation angle and jamming of the external objects.
Taiwan Patent Nos. M473049, M465006 and I388278 disclose various complex mechanisms that use a timer to interrupt pumping of cultivation liquid. However, the aquaponics system basically aims to adopt the concept of natural circulation function with minimum electronic devices. The aforesaid prior techniques, although can partly fix the problem, actually contradict this concept.